System and method for adjusting anode rod galvanic corrosion

Abstract

Systems and methods for adjusting anode rod galvanic corrosion are provided. An exemplary water heater includes a tank for holding a volume of water. The water heater also includes an anode rod extending into the water and electrically connected to an electrical ground such that a galvanic current flows from the anode rod to the electrical ground. The water heater includes at least one heating element configured to heat the water when energized. The water heater also includes a resistor configuration connected between the anode rod and the electrical ground such that the galvanic current flows through the resistor configuration. The resistor configuration provides a variable resistance.

What is claimed is: 
     
       1. A method for operating a water heater, the method comprising:
 connecting one or more resistors between an anode rod extending into a volume of water stored by the water heater and an electrical ground such that a galvanic current flows from the anode rod through the one or more resistors to the electrical ground; 
 receiving a feedback signal describing one or more electrical attributes of the volume of water stored in the water heater; 
 after receiving the feedback signal determining a difference between the feedback signal and a target value; and 
 after determining the difference, adjusting a resistance provided by the one or more resistors based on the feedback signal such that the galvanic current is either increased or decreased; 
 wherein adjusting the resistance provided by the one or more resistors comprises adjusting the resistance provided by the one or more resistors when the difference is greater than threshold difference. 
 
     
     
       2. The method of  claim 1 , wherein receiving a feedback signal describing one or more electrical attributes of a volume of water comprises receiving the feedback signal from a water measurement probe, the feedback signal describing a water resistivity. 
     
     
       3. The method of  claim 1 , wherein receiving a feedback signal describing one or more electrical attributes of a volume of water comprises receiving the feedback signal from a water measurement probe, the feedback signal describing a water conductivity. 
     
     
       4. The method of  claim 1 , wherein receiving a feedback signal describing one or more electrical attributes of a volume of water comprises receiving the feedback signal from a water measurement probe, the feedback signal describing a potential between the water measurement probe and a tank of the water heater. 
     
     
       5. The method of  claim 1 , further comprising, prior to adjusting the resistance but after determining a difference between the feedback signal and the target value:
 calculating an anticipated value of the one or more electrical attributes based on the feedback signal and a candidate resistance; and 
 determining a variance between the anticipated value and the target value; 
 wherein adjusting the resistance provided by the one or more resistors when the difference is greater than a threshold difference comprises adjusting the resistance provided by the one or more resistors to the candidate resistance when the difference is greater than the threshold difference and the variance is less than a threshold variance. 
 
     
     
       6. A method of operating a water heater that includes a tank for holding a volume of water, an anode rod that extends into the volume of water, and a resistor configuration connected in a path of galvanic current flow between the anode rod and an electrical ground, the resistor configuration providing a variable resistance, the method comprising:
 receiving, by a controller, a feedback signal from a probe positioned within the tank of the water heater, the feedback signal descriptive of one or more electrical attributes of the volume of water held in the tank; 
 adjusting, by the controller based at least in part on the feedback signal, the variable resistance provided by the resistor configuration to adjust a magnitude of the galvanic current flow between the anode rod and the electrical ground; 
 wherein adjusting, by the controller, the variable resistance provided by the resistor configuration comprises providing by the controller, one or more control signals to a resistance adjusting mechanism to adjust the variable resistance provided by the resistor configuration; and 
 wherein providing, by the control the one or more control sign is comprise causing, by the controller, actuation of at least one of a plurality of jumpers respectively associated with a plurality of resistors, the plurality of resistors in parallel, each of the plurality of jumpers selectively allowing or disallowing flow of the galvanic current though the associated resistor. 
 
     
     
       7. The method of  claim 6 , wherein receiving, by the controller, the feedback signal from the probe comprises receiving the feedback signal that describes a water resistivity of the volume of water. 
     
     
       8. The method of  claim 6 , wherein receiving, by the controller, the feedback signal from the probe comprises receiving the feedback signal that describes a water conductivity of the volume of water. 
     
     
       9. The method of  claim 6 , wherein receiving, by the controller, the feedback signal from the probe comprises receiving the feedback signal that describes a voltage potential between the probe and the tank of the water heater. 
     
     
       10. The method of  claim 6 , further comprising:
 comparing, by the controller, a measurement value included in the feedback signal to a target value; 
 wherein adjusting, by the controller based at least in part on the feedback signal, the variable resistance provided by the resistor configuration comprises adjusting, by the controller, the variable resistance provided by the resistor configuration based at least in part on the comparison of the measurement value to the target value. 
 
     
     
       11. The method of  claim 10 , wherein adjusting, by the controller, the variable resistance provided by the resistor configuration based at least in part on the comparison of the measurement value to the target value comprises:
 when a difference between the measurement value and the target value is greater than a threshold value, adjusting, by the controller, the variable resistance provided by the resistor configuration; and 
 when the difference between the measurement value and the target value is not greater than the threshold value:
 delaying, by the controller, for a period of time; and 
 after delaying for the period of time, obtaining, by the controller, an additional measurement value to compare to the target value. 
 
 
     
     
       12. The method of  claim 6 , wherein adjusting, by the controller based at least in part on the feedback signal, the variable resistance provided by the resistor configuration comprises:
 calculating, by the controller based on the feedback signal, an anticipated value of the one or more electrical attributes for a candidate resistance; 
 determining, by the controller, a variance between the anticipated value and a target value; and 
 adjusting, by the controller, the variable resistance provided by the resistor configuration to the candidate resistance when the variance is less than a threshold variance. 
 
     
     
       13. A method of operating a water heater that includes a tank for holding a volume of water, an anode rod that extends into the volume of water, and a resistor configuration connected in a path of galvanic current flow between the anode rod and an electrical ground, the resistor configuration providing a variable resistance, the method comprising:
 receiving, by a controller, a feedback signal from a probe positioned within the tank of the water heater, the feedback signal descriptive of one or more electrical attributes of the volume of water held in the tank; 
 adjusting, by the controller based at least in part on the feedback signal, the variable resistance provided by the resistor configuration to adjust a magnitude of the galvanic current flow between the anode rod and the electrical ground; 
 wherein adjusting, by the controller based at least in part on the feedback signal, the variable resistance provided by the resistor configuration comprises:
 calculating, by the controller based on the feedback signal, an anticipated value of the one or more electrical attributes for a candidate resistance; 
 determining, by the controller, a variance between the anticipated value and a target value; and 
 adjusting, by the controller, the variable resistance provided by the resistor configuration to the candidate resistance when the variance is less than a threshold variance. 
 
 
     
     
       14. The method of  claim 13 , wherein receiving, by the controller, the feedback signal from the probe comprises receiving the feedback signal that describes a water resistivity of the volume of water. 
     
     
       15. The method of  claim 13 , wherein receiving, by the controller, the feedback signal from the probe comprises receiving the feedback signal that describes a water conductivity of the volume of water. 
     
     
       16. The method of  claim 13 , wherein receiving, by the controller, the feedback signal from the probe comprises receiving the feedback signal that describes a voltage potential between the probe and the tank of the water heater. 
     
     
       17. The method of  claim 13 , wherein adjusting, by the controller, the variable resistance provided by the resistor configuration comprises providing, by the controller, one or more control signals to a resistance adjusting mechanism to adjust the variable resistance provided by the resistor configuration. 
     
     
       18. The method of  claim 17 , wherein providing, by the controller, the one or more control signals comprises causing, by the controller, actuation of at least one of a plurality of switching devices respectively associated with a plurality of resistors, the plurality of resistors in parallel, each of the plurality of switching devices selectively allowing or disallowing flow of the galvanic current though the associated resistor.